A screen printing machine includes a printing device provided on a base. The printing device includes a board positioning mechanism, a mask plate, a squeegee, a paste supply cylinder and the like and is configured to execute screen printing work on a board which is conveyed and positioned by a board conveying path. In the screen printing machine as described above, a portion above the base is covered by a cover member, and the printing device is accommodated within a working compartment formed in a space defined by the base and the cover member.
In the screen printing work, the temperature within the working compartment needs to be controlled from the reason that the viscosity of paste is maintained at a proper value so as to ensure a constant quality. Because of this, there is a screen printing machine which includes a blower unit for blowing temperature-controlled air into a working compartment (Patent Document 1).
On the other hand, among screen printing machines, there is provided a type of screen printing machine in which two printing devices are provided within a space surrounded by a base and a cover member such that these two printing machines can simultaneously perform respective screen printing operations. In a screen printing machine, an access door is provided in a cover member which is used when the operator performs maintenance work on the printing device, whereby the operator opens this access door to allow access to the printing device. In the printing machine including the two printing devices provided on the base, a plurality of access doors are provided in positions which correspond to the printing devices so as to give access to the respective printing devices.